Phone’s Wi-Fi hotspot acts as SOS beacon in disasters

An app that turns a smartphone into a wireless SOS beacon could one day help rescuers track down people who have been trapped in collapsed buildings after natural disasters or bombings.

Because such events often knock out phone and internet networks, trapped people cannot make calls, send texts or email for help. “They are in an island of non-connectivity,” says Amro Al-Akkad, an engineer with the Fraunhofer Institute for Applied Information Technology in St Augustin, Germany.

Then his colleague, Leonardo Ramirez, noticed the mischievous messages his neighbours broadcast by changing the name of their home Wi-Fi networks, such as “no smoking on the balcony” and “turn the noise down”. He realised that you could use an app to insert a short SOS message into the name field of a phone’s Wi-Fi hotspot, too, which broadcasts a radio signal without requiring internet access. Rescuers can read the message with their own Wi-Fi app.

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The team consulted emergency workers from the Haiti and Fukushima disasters and developed a “victim app” and a “seeker app”. “They wanted it simple, unencrypted and smart,” says Al-Akkad.That meant avoiding known problems like low-power, low-range Bluetooth radio links, which often fail to connect – or “pair” – with each other amid the clutter of metallic debris in broken buildings. So they stuck to the much more robust and receivable Wi-Fi radio.

Victim app

With the victim app a trapped person can write a 27-character message such as “broken leg stuck in bank” or “need help fire on 4th floor” and a seeker app up to 100 metres away can pick it up. The app found two “trapped” people in a large-scale, simulated terrorist attack at a seaside chemical plant in Stavanger, Norway – an exercise organised by the Norway-based research organisation Sintef.

They want the victim app to be incorporated in Android or iOS operating systems, but they are also investigating a way to distribute the app virally at a disaster scene. “We need this as no one expects to be in a disaster and won’t download the app,” says Al-Akkad.

The fact that the system works on standard hardware impresses Per Ola Kristensson, an interactive systems engineer at the University of St Andrews in the UK&colon; “It’s interesting how they have appropriated widely deployed smartphone hardware in a new and unexpected way. That’s the beauty of software. It’s much easier than trying to push newly invented hardware into people’s hands.”